早期糖尿病大鼠视网膜毛细血管及视细胞超微结构变化

Ultrastructural pathological changes in retinal capillaries and photoreceptors in early diabetic rats

目的 :探讨糖尿病性视网膜病变 (diabeticretinopathy,DR .简称糖网病 )早期大鼠视网膜毛细血管及视细胞 (视感受器 )的病变发展规律。方法 :选择健康成年Wistar大鼠 ,随机分成正常对照组 (CON)、糖尿病 1个月 (DM1)组、3个月 (DM3)组和 6个月 (DM6 )组。按 5 5mg/kg体重一次性向腹腔内注射链脲佐菌素 (STZ)诱导大鼠糖尿病。取大鼠视网膜制备成超薄切片 ,用透射电镜观察并进行计算机图像分析。结果 :病程 1个月时 ,周细胞和内皮细胞核异染色质聚集靠边 ,视杆细胞膜盘模糊不清 ,膜盘间隙略有扩大。病程 3个月时 ,周细胞和内皮细胞异染色质聚集严重 ,毛细血管扩张 ,基底膜增厚 ,膜盘间隙明显扩大 ,并发生局灶性断裂、溶解。视杆细胞膜固缩、异染色质浓集。视杆内节线粒体肿胀、甚至发生空泡变性。病程 6个月时 ,以上改变更加严重 ,但毛细血管由扩张转为狭窄、变形 ,甚至闭塞。结论 :糖网病早期大鼠视网膜毛细血管出现病变的同时 ,亦出现视感受器超微结构的改变。

Objective:To investigate ultrastructural pathological regularity in retinal capillaries and photoreceptors in rats with early diabetic retinopathy.Methods:Healthy adult Wistar rats were chosen and divided into the following groups: normal group(CON),diabetes mellitus at one month(DM1),three months(DM3) and six months(DM6). Diabetes was induced in rats with a single dose of 55mg/kg of streptozotocin(STZ) administered intraperitoneally. Ultrathin sections were taken from the rat retinas,observed under transmission electron microscope and analyzed by an electronic computer image processing analytical system.Results:In DM1,the metachromatin of the pericytes and endothelial cells clumped together at the side. Membrane disks in rods were occluded and their spaces were slightly enlarged. In DM3,the nuclear metachromatin in the pericytes and endothelial cells clumped together in a dense mass at the side,the capillaries expanded and the basement membrane increased. The membrane disk spaces were distinctly enlarged,dividing and dissolving locally. Rod cell nuclei showed pyknosis and chromatin condensation. The condrocyte in the inner segments of the rods swelled and even denatured. In DM6,all the above changes appeared to be more severe,while the capillaries became narrow,deformed,and even occluded.Conclusion:In the early stage of DR in rats,retinal capillaries changed simultaneously with the appearance of ultrastructural changes in photoreceptors. As diabetes mellitus progressed,pathological conditions in the capillaries and photoreceptors gradually deteriorated. [FK(WB80011?6]